Measure carefully, I thought I did but had to sit the frame on top of the nails.  I don't consider that a problem, since you can't see it unless told about it. I was a quarter inch off and could not make it work.  But,,- it held all my knick knacks and I really love it. I had a large picture there but this does not overpower the space. It is perfect. 

Pros: Simple to assemble, took 30 seconds. Just measure more carefully than I did. Look great 
Cons: no cons